Power strap tensioning tool



y 3, 1966 H. c. LINGLE 3,249,131

POWER STRAP TENSIONING TOOL Filed Sept. 24, 1959 3 Sheets-Sheet 1 INVENTOR. Am 6 y 3, 1966 H. c. LINGLE 3,249,131

POWER STRAP TENSIONING TOOL Filed Sept. 24, 1959 5 Sheets-Sheet 2 H if; 2; 156

INVENTOR. l/a/kwm C May 3, 1966 H. c. LINGLE 3,249,131

POWER STRAP TENSIONING TOOL Filed Sept. 24, 1959 3 Sheets-Sheet 5 INVEN TOR. Am 0. O1

WWW/406% United States Patent 3,249,131 POWER STRAP TENSIONING TO0L Harrison C. Lingle, Wilmette, 11]., assignor to SIgnode Corporation, a corporation of Delaware Filed Sept. 24, 1959, Ser. No. 842,005 11 Claims. (Cl. 14093.4)

The present invention relates to power strap tensioning tools, and in particular to a new and improved pusher type power strap tensioning tool.

In pusher type strap tensioning tools the opposite ends of the strapping are disposed at the opposite faces of the foot portion of the tool frame. One end of the strapping is stationary and extends through a partially closed seal blank and bent under. The flange portions of the seal blank may be folded over and disposed parallel to the back plate. The blank is snugged against the tool frame so that the toe or tip of the foot portion engages the seal blank flanges during the strap tensioning operation. The other end of the strapping, which is threaded through the seal blank, is pulled across the foot portion of the frame and away from the seal blank.

Considerable difiiculty has been encountered with certain features of this type of tool in power embodiments. For example, the tensioning wheel tends to :mar or scar the surface of the frame part or foot over which themovable strapping portion is drawn, and the tensioning wheel dulls when run without strap, thereby preventing an efficient operation of the tool.

When high strap tensioning forces are employed, such tools tend to cut through and destroy the seal blank before ceasing to move the strapping in the tensioning direction.

One of the features of the present invention is to provide a mechanism whereby the strap tensioning wheel will normally be held away from the frame surface over which the movable strapping end extends, to prevent it from being marred or scarred, and the tensioning wheel from being dulled.

This tool also features a novel breaker element which coacts with the foot of the tool securely to hold the standing strapping end while the strapping is broken away from the loop of strapping extending around the bundle and adjacent the joint.

Therefore, the principal object of the present invention is to provide a new and improved pusher type strap tensioning tool incorporating a power strap tensioning mechanism having the foregoing briefly discussed advantages, and overcoming the disadvantages of known'tools of the same type.

Another object is to provide a new and improved pusher type power strap tensioning tool wherein the strap tensioning wheel is normally held away from the frame portion over which the movable strap end extends and is adapted to slide, but may move toward that frame portion during the strap tensioning operation firmly to engage the trapping during that operation.

Another object is to provide a new and improved power actuated strap tensioning tool having a rockable wear pad mounted in the foot portion of the tool to insure engagement of the tensioning wheel across the full width of the strapping during the strap tensioning operation.

Another object is to provide a new and improved pusher type power actuated strap tensioning tool wherein there is provided a novel breaker foot and nose element, which coact to clamp that strapping portion which is to be broken from the strapping passed about the bundle while the tool (and gripped strapping) is rocked adjacent the joint in order to rupture the strapping.

Another object is to provide a new and improved heavy duty pusher type power strap tensioning tool which ice is relatively simple in construction, sturdy, comparatively light in weight, and easy to operate.

Other objects and advantages will become apparent from the following description taken in conjunction with the accompanying drawings, wherein FIG. 1 is an elevational view of the pusher type power strap tensioning tool of the present invention;

FIG. 2 is a fragmentary plan view of the forward end of the tool;

FIG. 3 is an elevational view of the front end of the tool, partially broken into section to illustrate the drive from the .power motor to the tensioning wheel shaft;

FIG. 4 is a fragmentary sectional view, taken along the line 4-4 of FIG. 1, looking in the direction of the arrows;

FIG. 5 is a fragmentary sectional view, taken along the line 55 of FIG. 3, looking in the direction of the arrows;

FIG. 6 is an elevational view, on a smaller scale, illustrating the position of the tool during tensioning the strapping about the bundle; and a FIG. 7 is an elevational view, similar to FIG. 6, show- I ing the tool in the strap bending and breaking position subsequent to the formation of a tension resisting joint between the overlapped strapping ends.

The strap tensioning tool 10 of the present invention includes a main or base frame 12 having a foot portion 14 adapted to rest upon or against the package or load B being bound, and to which a tension mechanism or auxiliary frame 16 is pivotally mounted. A strap tensioning wheel 18 of the serrated or knurled periphery type is rotatably carried by the tension mechanism frame 16 and is driven from. an air motor or other suitable power source 20 in a manner presently to be described.

The main or base frame 12 has a foot portion 14 which is adapted to be seated upon or rested against the bundle or load being bound during the strap tensioning operation. Upstanding from this portion is an intermediate section 22 on the upper end of which there is formed an integral boss 24 having a bore 26 therethrough to carry a pivot shaft 28 for the auxiliary or tensioning mechanism frame 16.

The foot portion 14 extends laterally from the vertical portion 22 and underlies the tensioning wheel 18 as well as the laterally extending boss 24. The foot portion has a relatively plane upper surface 30 across which-the movable end S of the strapping is adapted to extend, and has an underside composed of a relatively fiat portion 32 which is generally parallel to the surface 30,

and an inclined portion 34 sloping upwardly toward a toe or lip 36 at the forward end of the tool- When the tool is in strap tensioning position and power is applied to the tensioning wheel 18, the fixed end S of the strapping extends under the foot portion 14 and particularly under the inclined surface 34, the tool being held in the position shown in FIG. 6, with the inclined portion 34 resting on or against the surface of the bundle or load B. The opposite and standing end S of the strapping extends across the surface 30 of the foot portion 14, and under the tensioning Wheel 18, and therefore slightly upwardly and outwardly at an angle from the bundle (FIG. 6). However, this position is that which obtains during the tensioning operation, and when the strap tensioning is first initiated the tool may well be in the position shown in FIG. 1, with the underside 32 of the foot portion 14 resting against the strapping end S and on the bundle or load B.

A hardened steel circular wear pad 38 is fitted in a recess 40 formed in the foot portion 14 with the surface of the wear pad projecting just slightly above the foot portion surface 30 and underlying the tensioning wheel 18 (FIG. 1). The wear pad is suitably secured in place by a roll pin 42 extending through aligned openings in the foot portion 14 and the wear pad 38 adjacent the end of a diameter thereof. The wear pad 38 is beveled at 41 on approximately one-half of the bottom surface in such a manner that it can rock along a line 43 near its center and always position its top surface in parallel with the tensioning wheel 18.

The auxiliary or tensioning mechanism frame 16 includes an outer link 44 and a gear housing 46. At its upper end the outer link is apertured to receive the outer end of the pivot shaft 28 which is nonrotatably secured thereto by a roll pin 48 extending through apertures 'in the link 44 and shaft 28. At its lower end, which is offset outwardly from its upper end (FIG. 3), the link is apertured to receive a sleeve bearing 50 in which is journaledthe outer end of tensioning wheel shaft 52.

The tensioning wheel 18 is nonrotatably mounted on the tensioning wheel shaft 52 on a hexagonal portion thereof in a well known manner, and is positioned between the lower end of the link 44 and the vertically extending portion 22 of the main frame, as best seen in FIGS. 2 and 3.

The gear housing 46 comprises a casting 54 having a chamber 56 therein which is closed at its lower face by a plate 58. At its upper forward end the casting 54 is formed with a boss 60 having a bore 62 therethrough into which the pivot shaft 28 extends. The outer end of the pivot shaft projecting into the bore 62 is threaded to receive an Allen nut 64 which projects slightly from a counterbore section of the bore 62. In this manner the gear housing portion 46 of the tensioning mechanism frame 16, and the power motor 20, are pivotally mounted .on the main frame 12.

The casting 54 has a rearwardly projecting generally tubular portion 66 which terminates in a threaded boss (not shown) onto which a collar 68 is threaded to mount,

the air motor 20 on the gear housing 46. The air motor 20 is of a conventional type and is provided with a manually operable valve ring 70 adjacent its outer end for controlling the air supply to the motor and with a fitting 72 by means of which the air line 74 is connected to the motor.

The air motor 20 drives a shaft 76 on which is formed a worm 78. The shaft and worm project into the gear chamber 56 in the casting 54 so that the worm meshes with a worm wheel 80 which is nonrotatably mounted on a splined section 82 of the tensioning wheel shaft 52. 'The shaft 52 is journaled in the gear housing casting 54 on a pair of ballbearings 84 disposed at either side of the worm wheel 80 and the splined section 82 of the shaft. The shaft 52 projects from the gear housing 46 through an opening 86 which is closed by a seal retainer 88 and a seal 90, which are held in position by a C-clip 92 engaging in an appropriate recessin the casting 54.

The shaft 52 extends between the two movable parts of the auxiliary frame 16, namely, the gear housing 46 and the outer link 44, and in doing so extends through an enlarged opening 94in the vertical portion 22 of the main frame (FIG. 1). It is thus possible for the auxiliary frame 16 to pivot on the pin 28 with respect to the main frame 12 to move the tensioning wheel 18 toward and away from the foot portion 14 and the wear pad 38 so that the strapping may be inserted between the upper surface of the wear pad 38 and the tensioning wheel during loading of the tool, and so that the tensioning wheel 18 will always be held in tight engagement with the strapping during the tensioning operation, as will be explained more fully hereinafter.

The auxiliary frame 16 and the tensioning wheel 18 are biased in the clockwise direction toward the wear pad 38 (FIG. 1) by a foot spring 96 located in a recess 98 in the main frame boss 24 and has one end 100 hooked against an edge of the vertical section 22 and the opposite end 102 hooked over a pin 104 carried in the gear housing 46, the spring 96 encircling'a projection 106 of the boss 24 surrounding the pivot pin 28.

To facilitate lifting the tensioning wheel 18 away from the wear pad 38, there is provided a handle 108 which has a downwardly and forwardly extending portion 110 fitted into a slot 112 (FIGS. 1 and 2) on that face of the vertical main frame portion 22 adjacent the gear housing 46, and in which it is retained by a fiat head cap screw 114.

The handle has a portion 116 extending away from the frame 12 and generally overlying the air motor 20 (FIGS. 1 and 3). This enables the operator to encircle with one hand the handle portion 116 and the motor 20 or the rear cylindrical portion 66 of the gear housing casting 54 and squeeze them together to raise the tensioning wheel 18 from the wear pad 38 to enable the strapping to be inserted therebetween. However, the handle does not extend suificiently far rearwardly to interfere with the manipulation of the tool and the operation of the valve control collar 70.

Normally the tensioning wheel 18 will be held away from the foot portion 14 and the surface of the wear pad 38 by means of a stop pin 118 (FIG. 4) which has a square (or other noncylindrically shaped) shank 119. The pin is movably mounted in a bore 120 formed in a boss 122 on the main frame 12 toward the rear or right end (FIG. 1) of the foot portion 14, but offset therefrom and generally in line with the vertical portion 22 so as not to interfere with the path of movement of the standing strapping end S. The pin 118 has a head 124 engaging a hollow screw 121 that restrains it against movement outwardly of the bore. The hollow screw 121 is threaded into the tapped outer end of the bore 120 and has a bore 123 shaped complementally to the pin shank 119 which slidably extends through it. The position of the stop screw 121, and thus the clearance between the tensioning wheel 18. and the wear pad 38, is adjusted by turning the square pin shank 119. It is preferred that this clearance be about .005", and when this adjustment is made the hollow screw 121 can be locked in place by set screw 126 threaded into the boss 122 and againt the hollow screw. The pin 118 is. biased. outwardly by a spring 128 confined between the head 124 and the bottom of the bore 120.

The outer end of the pin shank 119 is adapted to be contacted by a laterally extending lug 130 formed on the gear housing casting 54, as shown best in FIGS. 1, 2, and 4. When there is no strapping in the tool the lug 130 contacts the outer end of the shank 119 and the force exerted by the spring 128. is suflicient to prevent the force exerted by the foot spring 96 from bringing the tensioning wheel 18 into contact with the surface of the wear pad 38, and therefore any inadvertent operation of the motor 20 when the tool is not loaded with strap will not cause the wheel to rotate against the wear pad surface with an abrading and dulling action. The tensioning wheel 18 is free to bite into the strapping with great driving force as the strap tension pulls the tensioning wheel toward the foot 14 overcoming the effect of the resilient stop.

At the toe end of the foot portion 14 is an angularly positioned strap. breaker element 132, which is pivotally mounted on a bolt 136 and comprises a member having a nose 134 biased toward and adapted to be pressed against the surface 30 of the foot portion 14 at the toe 36 and aligned therewith. The pivot bolt 136 extends through the wall 22 and at its opposite and threaded end is'fitted with a lock nut 138 to secure it against inadvertent loosening. The breaker element 132 has a generally triangular shape in cross section, being formed at its rear end with an enlarged bearing portion 140 which has a transverse slot 142 formed therein, in which is positioned a biasing nose spring 144 surrounding the pivot bolt 136 and having an end 146-hooked over the top edge of the.

140 of the breaker element 132. The breaker element 36 thereof, and is at least as wide as the strapping with V which the tool is adapted to be used. In the case of heavy duty strapping this width would be 1%.". At its outer edge the nose element 132 is curved or relieved at 152 to facilitate the insertion of strapping between the element 132 and the foot portion 14 of the tool against the clamping action of the spring 144.

In FIG. .4 the strap tensioning Wheel is shown in phantom lines, and it will be observed that its drum-like periphery 154 in the normal or relaxed conditioned of the tool has its outside edge closer to the surface of the wear pad than its inside edge 158. As the tensioning wheel 18 initially engages the strapping between it and the wear pad 38 it rocks the latter about the pivot line 43 so that its upper surface is parallel to the surface of the tensioning wheel 18 and the teeth of the wheel may bite into the strapping across the full width of the strapping and of the wheel. As the tensioning operation progresses and the strapping is moved under the wheel from left to right (FIG. 1), there is an increase in the gripping pressure of the serrated wheel periphery on the strapping end S. This increase in pressure of the wheel against the strapping tends to bend the foot portion 14 downwardly and outwardly, or in the clockwise direction about the frame (FIG. 4). As this occurs the wear pad 38 rocks about the pivot line 43 in the recess 40 so that its surface will maintain its parallelism with the wheel periphery and the engagement of the wheel across the width of the strapping. This insures constant driving engagement between the tensioning wheel and the strapping, and that the wheel willwear evenly across the width of its surface, giving it a longer useful life thanwould be the case were the wheel to dull more rapidly near its outer edge 156, as would be the case if the wear pad had no aligning action.

During the tensioning operation the lug 130 will approach the boss 122 and push the stop pin 118 downwardly into the bore 120 and against the force exerted by the spring 128. The spring is not sufficiently strong to prevent this action. In fact, one function of this spring is to allow this relative movement to take place to give full effect to the energizing force of the strap tension on the tensioning wheel 18. For this reason a resilient stop has a decided advantage over a fixed stop. With a fixed stop an effective clamping action between the tensioning wheel 18 and the strapping end S might not be obtained.

At the outset of the banding operation, the strapping is wrapped about the package, bundle, or load B and one endS thereof is inserted through a thread-on type of seal blank. That end of the strapping is then passed completely about the bundle so that it again may be threaded through the seal blank C with a portion S projecting therefrom. This small end S" is folded back and under the flanges of the seal blank C and the strapping portion S is then positioned under the foot portion 14 of the tool 10. The portion S which projects from the seal blank C is slid edgewise under the breaker nose element 132 (which is lifted against the force of the biasing spring 144) and under the tensioning wheel 18 which has been raised from the wear pad 38 by squeezing together the handle 108 and the motor 20. The tool is slid along the strap S until the breaker nose 134 abuts the seal blank C and the handle 108 and motor 20 are released to clamp' the strapping end S between the Wheel 18 and the wear pad 38.

Air is admitted to the motor 20 by rotating the collar 70 to the on position and the tensioning wheel 18 is driven in the counterclockwise direction (FIG. 1) to draw the strapping S from left to right (FIG. 6) across the wear pad and tension it tightly about the bundle or load B. When the strapping has been adequately tensioned, the motor 20 stalls and the tensioning Wheel 18 will stop. When the motor 20 stalls to stop the strap tensioning, a joint forming tool, such as that disclosed in Harrison C. Lingle Patent No. 2,831,381, dated April 22, 1958, is applied to form a joint between the overlapping strapping portions S and S and the embracing seal blank C.

During the strap tensioning operation the breaker element 132 holds the strapping end S tightly against the foot portion 14 as it slides therebetween because of the force exerted by the spring 144 and especially because of the force of the seal blank C against the nose 134 of the breaker element 132. This energizing force of theseal blank against the breaker element imparts a counterclockwise rotational movement (FIGS. 1, 5, and 6) to the breaker element that causes it to bear tightly against the strapping. After the joint has been formed the tool is rocked from the position shown in FIG. 6 to that shown in FIG. 7, and the strapping S is broken over the corner of the nose 134 of the breaker element 132 immediately adjacent the .seal blank portion of the completed joint. The strap breaks easily because of the energizing action of the breaker element which bears down on the strapping and provides a sharp tight corner for the strapping to break against. The amount of this energizing force is governed by the height and position of the pivot pin 136 above the top surface of the foot 14 which determines the angle between the breaker element 132 and the foot 14. Too great an angle causes too much of a downward force on the strapping and a consequent loss in tension. Too small an angle does not give adequate holding force by the breaker element to insure clean and easy breaking of the strapping. The angle between the top surface of the foot 14 and the center line of the breaker element in the tool illustrated is about 25.

A stop member 160 projecting forwardly of the base frame with a stop surface 162 aligned with the breaker element nose 134 and frame foot portion toe 36, limits the forward (or counterclockwise, FIG. 7) rocking movement of the tool to so that the top of the seal blank C is not pried open around the top corner of the breaker element 132.

From the foregoing description it will be apparent that the objectives which were claimed for this invention at the outset of this description have been fully attained.

While a preferred embodiment of the power strap tensioning tool has been shown and described, it will be apparent that numerous modifications and variations thereof may be made without departing from the underlying principles of the invention. It is there-fore desired, by the following claims, to include within the scope of the invention all such variations and modifications by which substantially the results of this invention may be obtained through the use of substantially the same or equivalent means.

What is claimed as new and United States Letters Patent is:

1. A tool for applying tension to strapping encircling a bundle or the like, comprising in combination, a main frame having a laterally extending foot portion across the surface of which one end of the strapping is adapted to extend and slide, a tensioning wheel having a cylindrical strap engaging surface, means mounting said tensioning wheel for rotation in strap tensioning direction in a position closely adjacent said foot portion to engage the strapping end extending thereacross, said means being pivotally mounted on said-frame for limited swinging movement of said tensioning wheel toward and away from said foot portion and strap engaging position, biasing means acting on said mounting means for urging said tensioning wheel into strap engaging position, and resilient stop means interposed between said frame and said mounting means and limiting movement of said tendesired to be secured by drical strap engaging surface, means mounting said tensioning wheel for rotation in strap tensioning direction a in a position closely adjacent said foot portion to engage the strapping end extending thereacross, said tensioning wheel normally having its outer edge closer to said foot portion surface than its inner edge, said means being pivotally mounted on said frame for limited swinging movement of said tensioning wheel toward and away from said foot portion and strap engaging position, a wear pad mounted in said foot portion below said tensioning wheel and being rockable along a line parallel to the longitudinal extension of the strapping, biasing spring means acting on said mounting means for urging said tensioning wheel 5 into strap engaging position, and resilient stop means interposed between said frame and said mounting means and limiting movement of said tensioning wheel toward said foot portion when there is no strapping in the tool but permitting movement of said wheel into engagement with the strapping during the strap tensioning operation, said stop means including a spring pressed plunger carried by said frame and engageable by a part on said mounting means.

3. A tool for applying tension to strapping encircling a bundle or the like, comprising in combination, a main frame having a laterally extending foot portion across the surface of which one end of the strapping is adapted to extend and slide, a tensioning wheel having a cylindrical strap engaging surface, means mounting said tensioning wheel for rotation in strap tensioning direction in a position closely adjacent said foot portion to engage the strapping end extending thereacross, said tensioning wheel normally having its outer edge closer to said foot portion surface than its inner edge, said means being pivotally mounted on said frame for limited swinging movement of said tensioning wheel toward and away fromsaid foot portion and strap engaging position, a wear pad mounted in said foot portion below said tensioning wheel and being rockable along a line parallel to the longitudinal extension of the strapping, means connected to saidtensioning wheel for rotating the latter in strap tensioning direction which rotation tends to swing said wheel toward said foot portion and said wear pad, biasing spring means acting on said mounting means for urging said tensioning wheel into strap engaging position, and resilient stop means interposed between said frame and said mounting means and limiting movement of said tensioning wheel toward said foot portion when there is no strapping in the tool but permitting movement of said wheel into engagement with the strapping during the strap tensioning operation, said stop means including a spring pressed plunger carried by said frame and engageable by a part on said mounting means.

4. A tool for applying tension to strapping encircling a bundle or the like, comprising in combination, a main frame having a laterally extending foot portion across the surface of which one end of the strapping is adapted to extend and slide, a tensioning wheel having a cylindrical strap engaging surface, means mounting said tensioning wheel for rotation in strap tensioning direction in a position out of parallel with and closely adjacent said foot portion surface to engage the strapping end extending thereacross, said means being pivotally mounted on said frame for limited swinging movement of said tensioning wheel toward and away from said foot portion and strap engaging position, means connected to said tensioning wheel for rotating the latter in strap tensioning direction,

a wear pad mounted in said foot portion below said tensioning wheel and being rockable into a position of parallelism with the periphery of said tensioning wheel along a line parallel to the longitudinal extension of the strapping, biasing spring means acting on said mounting means for urging said tensioning wheel into strap engaging position, and resilient stop means interposed between said frame and said mounting means, acting .in opposition to said biasing spring means, and limiting movement of said tenisoning wheel toward said foot portion when there is no strapping in the tool but permitting movement of said tensioning wheel into engagement with the strapping during the strap tensioning operation even though said foot portion be deflected, said stop means including a spring pressed plunger carried by said frame and engageable by a part on said mounting means.

5. A tool for applying tension to strapping encircling a bundle or the like, comprising in'combination, a main frame having a laterally extending foot portion across the surface of which one end of the strapping is adapted to extend and slide, a tensioning wheel having a cylindrical strap engaging surface, means mounting said tensioning wheel for rotation in strap tensioning direction in a position out of parallel with and closely adjacent said foot portion surface to engage the strapping end extending thereacross, said means being pivotally mounted on said frame for limited swinging movement of said tensioning wheel toward and away from said foot portion and strap engaging position, power means mounted on said mounting means and connected to said tensioning wheel for rotating the latter in strap tensioning direction, a wear pad mounted in'said foot portion below said tensioning wheel and being rockable into a position of parallelism with the periphery of said tensioning wheel along a line parallel to the longitudinal extension of the strapping, biasing spring means acting between said frame and said mounting means for urging said tensioning wheel into strap engaging position, and resilient stop means interposed between said frame and said mounting means, acting in opposition to said biasing spring means, and limiting movement of said tensioning wheel toward said foot portion when there is no strapping in the tool but permitting movement of said tensioning wheel into engagement with the strapping to rock said wear pad into a position of parallelism with said tensioning wheel regardless of any deflection of said foot portion during the strap tensioning operation, said stop means including a spring pressed plunger carried :by said frame and engageable by a part on said mounting means.

6. A tool for applying tension to strapping encircling a bundle or the like, comprising in combination, a main frame having a foot portion adapted to rest upon the 'bundle, said foot portion having a surface across which one end of the strapping is adapted to extend and slide while the other end of the strapping extends beneath said foot portion, said foot portion having a toe against which a seal blank through and about which said other end of the strapping is wrapped is adapted to abut to anchor said other end of the strapping during a strap tensioning operation, a rotatable strap tensioning wheel carried by said main frame over said foot portion and in a position to engage said one end of the strapping extending thereacross, a strap breaker element tapering toward a nose and pivotally mounted on said main frame at an acute angle therewith so that its nose is in alignment with said foot portion toe and against which the seal blank is also adapted to abut, means biasing said breaker nose toward said foot portion surface to assist the energizing effect of the strapping under tension forcing the tool against the seal blank in holding the strapping against said foot portion while the tool is rocked upwardly on said toe thereby to break the strapping held under tension between said ten-' sioning wheel and -a strap joint formed with the strapping ends and the seal blank, and stop means carried by said main frame to limit the upward rocking movement of the tool to prevent the held strapping from prying open the seal blank about the nose of said breaker element.

7. A tool for applying tension to strapping encircling a bundle or the like, comprising in combination, a main frame having a foot portion adapted to rest upon the bundle, said foot portion having a surface across which one end of the strapping is adapted to extend and slide while the other end of the strapping extends beneath said foot portion, said foot portion having a toe against which a seal blank through and about which said other end of the strapping is wrapped is adapted to abut to anchor said other end of the strapping during a strap tensioning operation, a power driven rotatable strap tensioning wheel carried by said main frame over said foot portion and in a position to engage said one end of the strapping extending thereacross, a strap breaker element tapering toward a nose and pivotally mounted on said main frame so that its nose is in alignment with said foot portion toe and is abutted against by the seal blank, means biasing said breaker nose toward said foot portion surface to assist the energizing effect of the strapping under tension forcing the tool against the seal blank in holding strapping against said foot portion while the tool is rocked upwardly on said toe thereby to break the strapping held under tension between said tensioning wheel and a strap joint formed with the strapping ends and the seal blank, and stop means having a stop face in alignment with said nose and said toe carried by said main frame to limit the upward rocking movement of the tool to prevent the held strapping from prying open the seal blank about the nose of said breaker element.

8. A tool for applying tension to strapping encircling a bundle or the like, comprising in combination, a main frame having a foot portion adapted to rest upon the bundle, said foot portion having a surface across which one end of the strapping is adapted to extend and slide, said foot portion having a toe against which the other end of the strapping is adapted to be anchored and to extend beneath said foot portion, a tensioning mechanism frame, a tensioning wheel having a cylindrical strap engaging surface, means journaling said tensioning wheel to said tensioning mechanism frame so that said cylindrical strap engaging surface is closely adjacent said foot portion surface, power means mounted on said tensioning mechanism frame and connected to said tensioning wheel to rotate the latter in strap tension applying dirction, means pivotally mounting said tensioning mechanism frame to said main frame for limited swinging movement of said tensioning wheel toward and away from said foot surface, biasing means acting on said tensioning mechanism frame for urging said tensioning wheel toward said foot portion surface, resilient stop means interposed between said frames and holding said tensioning wheel out of engagement with said foot portion surface when there is no strapping in the tool, said stop means including a spring pressed plunger carried by said main frame and engageable by a part on said tension mechanism frame, a strap breaker element tapering toward a nose pivotally mounted on said main frame so that said nose is in alignment with said foot portion toe, and means biasing said breaker nose toward said foot portion surface to hold the strapping thereagainst while the tool is rocked upwardly on said toe thereby to break strapping held under tension between a strap joint and said tensioning wheel.

9. A tool for applying tension to strapping encircling a bundle or the like, comprising in combination, a main frame having a foot portion adapted to rest upon the bundle, said foot portion having a surface across which the strapping is adapted to extend and slide while the other end of the strapping is anchored against and extends beneath said foot portion, a tensioning mechanism frame, a tensioning wheel, means journaling said tensioning wheel to said tensioning mechanism frame so that its cylindrical strap engaging surface is closely adjacent said foot portion surface, power means mounted on said tensioning mechanism frame and connected to said tensioning wheel to rotate the latter in strap tension applying direction, means pivotally mounting said tensioning mechanism frame to said main frame for limited swinging movement of said tensioning wheel toward and away from said foot surface, biasing means acting between said frame for urging said tensioning wheel toward said foot portion surface, resilient stop means interposed between said frames and normally limiting movement of said tensioning wheel toward said foot portion surface but permitting movement of said wheel toward said foot portion as said wheel is pulled down during a strap tensioning operation, said stop means including a spring pressed plungor carried by said main frame and engageable by a part on said tension mechanism frame, a strap breaker element tapering toward a nose pivotally mounted on said main frame so that said nose is in alignment with the toe of said foot portion, and means biasing said breaker nose toward said foot surface to hold the strapping thereagainst while the tool is rocked upwardly on said foot portion toe thereby to break strapping held under tension between a strap joint formed at said toe and said tensioning wheel.

10. A tool for applying tension to strapping encircling a bundle or the like, comprising in combination, a main frame having a foot portion adapted to rest upon the bundle, said foot portion having a surface across which the strapping is adapted to extend and slide while the other end of the strapping extends beneath said foot portion, a tensioning mechanism frame, a tensioning wheel, means journalling sai-d tensioning wheel to said tensioning mechanism frame in a position so that its cy lindrical strap engaging surface is closely adjacent said foot portion surface, power means mounted on said tensioning mechanism frame and connected to said tensioning wheel to rotate the latter in strap tension applying direction, means pivotally mounting said tensioning mechanism frame to said main frame for limited swinging movement of said tensioning wheel toward and away from said foot surface, biasing means acting between said frames for urging said tensioning wheel toward said foot portion surface, resilient stop means interposed between said frames and normally limiting movement of said tensioning wheel toward said foot portion surface when there is no strapping in the tool, said stop means including a spring pressed plunger carried by said main frame and engageable by a part on said tension mechanism frame, an 'angularly positioned strap breaker element tapering toward a nose pivotally mounted on said main frame so that said nose is in alignment with the toe of said foot portion and is engageable with a seal blank joining the strapping ends, and means biasing said breaker nose toward said foot surface to hold the strapping thereagainst while the tool is rocked upwardly on said toe thereby to break the strapping held under tension between a strap joint at the toe of said foot portion and the nose of said breaker element and said tensioning wheel.

11. A tool for applying tension to strapping encircling a bundle or the like, comprising in combination, :a main frame having a foot portion adapted to rest upon the bundle, said foot portion having a surface across which the strapping is adapted to extend and slide while the other end of the strapping extends beneath said foot portion, a tensioning mechanism frame, a tensioning wheel, means journaling said tensioning wheel to said tensioning mechanism frame in a position so that its cylindrical strap engaging surface is closely adjacent said foot portion surface, power means mounted on said tensioning mechanism frame and connected to said tensioning wheel to rotate the latter in strap tension applying direction, means pivotally mounting said ten-sioning mechanism frame to said main frame for limited swinging movement of said tensioning wheel toward and away from said foot surface, biasing means acting between said frames for urging said tensioning wheel toward said foot portion surface, re-

1 1 silient stop means interposed between said frames and normally limiting movement of said tensioning wheel toward said foot portion surface when there is no strapping in the tool, said stop means including a spring pressed plunger carried by said main irame and engageable by a part on said tension mechanism frame, an angularly positioned strap breaker element tapering toward a nose and pivotally mounted on said main frame so that said nose is in alignment with the toe of .said foot portion, said foot portion toe and said breaker element nose being adapted to be held in engagement with a seal blank through which the overlapped strapping ends are threaded by tension in the strapping between the blank and said tensioning Wheel, means biasing said breaker nose toward said foot surface and augmenting the energizing force of the seal blank against said breaker element nose in holding the strapping against said foot surface while the tool is rocked upwardly on said toe thereby to break the strapping held under tension between a strap joint and said tensioning wheel, and stop means having a stop face in alignment with said toe and said nose for limiting the rocking movement of the tool to prevent the held strapping from prying open the seal blank about the nose of said breaker element.

References Cited by the Examiner 5 UNITED STATES PATENTS 2,349,608 5/1 944 Bramble 14093.4 2,622,460 12/1952 Keeble 14093.2 2,661,030 12/1953 Crosby et a1. l40 93.4 2,882,934 4/1959 Gerrard 140-93.2 10 2,936,156 5/1960 Coupland 254-51 3,028,885 4/1962. Leslie et a1. 25451 FOREIGN PATENTS 721,177 12/1954 1 Great Britain.

CHARLES W. LANHAM, Primary Examiner.

WHITMORE A. WILTZ, WILLIAM F. PURDY, HAR- RISON R. .MOSELEY, JOSEPH B. STRIZAK,

Examiners.

I. R. HULEN, W. H. HOLT, L. A. LARSON,

Assistant Examiners. 

1. A TOOL FOR APPLYING TENSION TO STRAPPING ENCIRCLING A BUNDLE OR THE LIKE, COMPRISING IN COMBINATION, A MAIN FRAME HAVING A LATERALLY EXTENDING FOOT PORTION ACROSS THE SURFACE OF WHICH ONE END OF THE STRAPPING IS ADAPTED TO EXTEND AND SLIDE, A TENSIONING WHEEL HAVING A CYLINDRICAL STRAP ENGAGING SURFACE, MEANS MOUNTING SAID TENSIONING WHEEL FOR ROTATION IN STRAP TENSIONING DIRECTION IN A POSITION CLOSELY ADJACENT SAID FOOT PORTION TO ENGAGE THE STRAPPING END EXTENDING THEREACROSS, SAID MEANS BEING PIVOTALLY MOUNTED ON SAID FRAME FOR LIMITED SWINGING MOVEMENT OF SAID TENSIONING WHEEL TOWARD AND AWAY FROM SAID FOOT PORTION AND STRAP ENGAGING POSITION, BIASING MEANS ACTING ON SAID MOUNTING MEANS FOR URGING SAID TENSIONING WHEEL INTO STRAP ENGAGING POSITION, AND RESILIENT STOP MEANS INTERPOSED BETWEEN SAID FRAME AND SAID MOUNTING MEANS AND LIMITING MOVEMENT OF SAID TENSIONING WHEEL TOWARD SAID FOOT PORTION WHEN THERE IS NO STRAPPING IN THE TOOL, SAID STOP MEANS INCLUDING A SPRING PRESSED PLUNGER CARRIED BY SAID FRAME AND ENGAGEABLE BY A PART ON SAID MOUNTING MEANS. 